1. Field of the Invention
This invention pertains to a dehydrator apparatus for drying foodstuffs and the like having a plurality of vertically stacked food supporting trays or screens which provide for directing forced air flow through the dehydrator in an improved manner with minimal recirculation and reduced resistance to flow.
2. Background Art
This invention relates to dehydrator apparatus of the general type disclosed and claimed in my prior co-pending application identified hereinabove. The dehydrator apparatus described in application Ser. No. 077,900 comprises a cylindrical lightweight housing in which is disposed an electric motor driving a fan for circulating air through a plurality of vertically stacked cylindrical trays or screens mounted above the fan wherein heated air is circulated over and around foodstuffs supported by the trays to provide for dehydration of the food for storage and preservation. The present invention pertains to significant improvements in the apparatus disclosed in the abovementioned patent application which make said apparatus more efficient in operation and improves the dehydration process whereby foodstuffs treated by the apparatus may be kept for relatively long periods of time with no additional preservative treatment necessary.
In the art of dehydrator apparatus of the type which is suitable for use in the typical home kitchen it is important that an efficient, lightweight and low cost device be provided which is each to use and has the desired attributes of a home appliance. Although the present invention may be adapted to use on large scale commercial dehydrators or the like it is particularly adapted for the typical domestic kitchen.
An important consideration in providing an appliance which is suited for use in a typical domestic kitchen is that it use as little energy as possible and yet be effective in operation. It is, for example, important that a dryer or dehydrator be adapted to circulate ambient air heated to an elevated temperature to improve the moisture absorption capability of the air circulated through the dehydrator. The use of ambient air reduces the power requirements of a dehydrator and also reduces the temperature to which the food must be heated in order to provide sufficient moisture removal. Accordingly, it is desirable to provide for circulation of ambient air through the dehydrator apparatus with the flow being in substantially one direction over the food to be dehydrated to minimize recirculation so as to improve the rate of evaporation. It is also important to be able to provide sufficient air circulation and to raise the temperature of the air to a desired level for optimum moisture evaporation while at the same time minimizing the consumption of energy. Low energy consumption and quiet operation are both highly desired features in most home appliances including apparatus of the type represented by the present invention. However, prior art food dehydrator or dryer apparatus have not been particularly adapted for use as a typical kitchen appliance and are not particularly energy efficient.
A problem with some types of prior art dehydrating apparatus pertains to the arrangement whereby heated air is continually recirculated within an enclosure to provide the dehydrating function. The closed circulation type of apparatus is limited in its capability to absorb moisture because the air becomes saturated at a particular temperature and only by raising the temperature can more moisture be removed from the material being dehydrated.
In prior art dehydrator apparatus little effort has been made to improve the air flow over and around the food supporting trays or screens to maximize the moisture evaporation rate and at the same time minimize the air circulation power requirements and the energy consumed in heating the air to perform the drying function. The present invention is directed to improvements in apparatus for alleviating both of these deficiencies in prior art dehydrators.